International Giant Otter Studbook Husbandry and Management

Their remaining foot parts were healthy, natural, and brown in appearance. Although, 3 to 4
years before, these otters were housed in enclosures where the majority of the enclosure
land/floor area or all of it was hard surfaces and in some cases the land area was also
insufficient because of inappropriate land to water ratios. They lived in the aforementioned
circumstances for most of their lives. See the foot recovery history of these individuals in the
paragraph below. Foot condition studies will be continued at Dortmund. It is highly
recommended that other institutions carry out similar studies.
One recovered otter, at the time of Groenendijk’s observation, had been housed in an
enclosure nearly entirely covered with soft substrates (mostly sand and the remaining
mulch) for only the past 2 months of his life. He, at that time, was housed with the otter
transferred from Brasilia Zoo and was in the process of recovering from unhealthy foot
condition. After the third month of his recovery, all of his toe and foot pads became offwhite/light
pink in color and the webbing and skin on his feet appeared healthy and brown
in color. This otter was previously housed on entirely concrete surfaces for the last 7 years
(including insufficient land area) and was housed in an enclosure where the greater portion of
the enclosure was covered with soft substrates for 4 years before this.
Of the otters (3 in total) that were kept for several or more years at Dortmund, their foot
condition was in significantly worse condition than before recovery (Gatz pers. comm.). Before
these otters recovered they all showed varying degrees of unhealthy foot condition, from
moderately unhealthy to very unhealthy (esp. when the addition of wet/damp conditions
aggravated the situation). The simple change of covering nearly the entire enclosure land and
floor area, which the majority or all was hard and smooth, with mulch or soft sand was the only
method used/needed to help the foot condition of these otters to recover. The recommended
substrate depths & types were provided. The land to water ratios had always been appropriate
in 2 of their 3 enclosures, and the 3 rd enclosure with insufficient land area because of
inappropriate ratios, was corrected. I.e. one pool was emptied and permanently filled with deep
mulch to create an appropriate ratio. When enclosure substrates become very damp or wet for
even short periods (i.e. days) or esp. during extended periods (e.g. during rainy periods or very
humid weather), their pads can become pink at least temporarily. The foot and toe pads of the
otter with completely healthy feet who is housed at the same zoo, remained totally brown during
these periods. I.e. this otters’ feet remained healthy during these times.
It is also interesting to note that the foot condition of the otter, previously discussed, reached full
recovery in only 3 months after being housed on an enclosure nearly entirely covered with soft
substrates as recommended. This otter was the only otter of the four aforementioned otters (all
of whom had long-term exposure to hard surfaces) that recovered so quickly. With the other
three otters, soft substrates were increasingly added, over the course of 1 to 2 years, until the
point where nearly all of the enclosure floor/land area was covered with soft surfaces. During
this time, these three otters underwent a slow, but very significant recovery. They did not have
off-white/light pink pads until nearly the entire surface was covered. No medical treatment was
administered to any of the recovered animals for their foot problems. Only the enclosure
conditions mentioned were changed. It is evident that full recovery can not be achieved and
recovery cannot be maintained until soft loose substrates and land to water ratios are provided as
recommended. It seems also that quicker recovery times can be achieved when nearly the entire
or all of the area is soft, as opposed to slowly increasing soft substrate cover. It also may be that
soft sand allows for quicker recovery than mulch. This is because the enclosure that the otter
with the quickest recovery time was housed in during recovery contained/s a significantly
greater ratio of sand to mulch compared to the enclosures in which the other three otters are
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